1．To our joy，they all________in mending the roof yesterday.
A．aided B．helped
C．supported D．assisted
解析：本题可从动词的用法上做出正确的判断。帮助某人做某事用aid sb.in doing sth.；或用help(sb.)to do sth.或help sb.with sth.；support意为“养活，支持”，
不符合句意。assist在此句中是不及物动词，assist in doing sth.意为“帮助做某事”。
答案：D
